Gas line control system and modular variable pressure controller

ABSTRACT

A pneumatically controlled assembly, system, method and device for the regulation of pressure of a gas as it flows in a pressurized line and including at least one loading valve which is set to respond to variations in pressure in conjunction with a pneumatically actuated process control valve so as to effectively regulate and maintain pressure of the gas in the pressurized line.

RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 15/218,186filed Jul. 25, 2016, titled “GAS LINE CONTROL SYSTEM AND MODULARVARIABLE PRESSURE CONTROLLER” now U.S. Pat. No. 10,234,047, which is adivisional of U.S. application Ser. No. 13/899,013, filed May 21, 2013,titled “GAS LINE CONTROL SYSTEM AND MODULAR VARIABLE PRESSURECONTROLLER” now U.S. Pat. No. 9,400,060, which claims priority to U.S.Provisional Application No. 61/649,460 titled “Gas Line Control System”and filed on May 21, 2012 as well as U.S. Provisional Application No.61/825,408 titled “Gas Line Control System,” filed on May 20, 2013. The'047 and '060 patents, as well as the '460 and '408 provisionalapplications are all incorporated herein by reference.

Further, U.S. Pat. No. 5,762,102 to Rimboym, titled “PneumaticallyControlled No-Bleed Valve And Variable Pressure Regulator” issued toBecker Precision Equipment, Inc. on Jun. 9, 1998, is also incorporatedherein by reference.

TECHNICAL FIELD OF THE INVENTION

The present device relates to devices and systems for regulation andcontrol of pressure in pressurized gas delivery lines. Particularly, thepresent device and system relate to a variable pressure controller (VPC)for regulation and control of fluid flow in a delivery line.

BACKGROUND OF THE INVENTION

Pressure regulators equipped with variable pressure regulator pilotvalves are used as operating regulators, monitors, stand-by regulatorsand relief valves. Prior to the invention of U.S. Pat. No. 5,762,102,such valves were designed to maintain the desired pressure of fluid in adelivery line by operating with a constant “bleed” from the valve. Thiswas not only wasteful but, in the case of some fluids, wasenvironmentally undesirable. Environmental costs and problems are causedby discharge of pollutants to the air. Bleed gas from natural gaspipelines to the atmosphere year after year only adds to the growingenvironmental problem. Overall, industry estimates place the dischargeof natural gas to the atmosphere from a single controller operating withconstant bleed to the atmosphere, in excess of 300,000 standard cubicfeet (SCF) per year.

In the present invention, while the no-bleed controller is of import,embodiments of the present invention address problems with the followingkey features:

-   -   VPC with one common block and external manifolds;    -   VPC with two different internal loading valves;    -   VPC with Manual Operation Valve (Rotary Type)—attached via        manifold configuration;    -   VPC with external insertion of Nozzle Assembly;    -   VPC-PID with variable gain;    -   System configurations above adaptable to diaphragm style rotary        pneumatic positioner via addition of proportional feedback        mechanism;    -   Double-acting, single-acting (reverse) and single-acting        (direct) in one common VPC configuration;    -   VPC with conditioning of output and exhaust flow paths via        manifolds;    -   Interchangeability of “normally open” and “normally closed”        internal loading valves in same body; and    -   Coupling of the “derivative” adjustable orifice on output of        “ID” models—derivative adjustment is configured in manifold        system and also incorporates “flow conditioning.”

These and other problems are solved by the present VPC device andsystem.

SUMMARY OF THE INVENTION

The following presents a simplified summary of embodiments of the systemand method of the disclosed invention. The summary is intended tointroduce particular useful elements, which may be critical to aparticular embodiment and optional for other embodiments. Though notspecifically summarized here, other critical and optional elements,including combinations of such elements, may also be possible.

Generally speaking, a pneumatic valve pressure controller system havinga fluid supply line and a variable pressure controller coupled to aprocess control valve within the supply line, is described.

In a particular embodiment, a supply regulator is fluidly coupled to thefluid supply line upstream of the process control valve and an actuatoris operably connected to the process control valve, the actuator havinga first pressure chamber and a second pressure chamber. A sensingdiaphragm connected to the fluid supply line determines a relativepressure in the fluid supply line on the outlet end side of the processcontrol valve, while a first loading valve is fluidly coupled to thefirst pressure chamber and responsive to the sensing diaphragm and asecond loading valve is fluidly coupled to the second pressure chamberand responsive to the sensing diaphragm. In such an embodiment, thefirst loading valve and the second loading valve open and close inresponse to the sensing diaphragm to change a position of the actuatorand thereby operate the process control valve.

In an embodiment of the method for controlling a fluid supply through adelivery line having a process control valve therein to maintain asupply side pressure and a delivery side pressure, and a pneumaticactuator having a first pressure chamber and a second pressure chamberand used to operate the process control valve, the steps include settinga delivery side target pressure range for the fluid supply, sensing thedelivery side pressure, and operating the pneumatic actuator to eithermaintain the actuator in a static state when the delivery side pressureis within the target range or move the actuator to adjust the processcontrol valve position when the delivery side pressure is outside thetarget range.

In a specific embodiment of the method, the first and second pressurechambers of the actuator are responsive to a first loading valve fluidlycoupled to the first pressure chamber and a second loading valve fluidlycoupled to the second pressure chamber, and the first loading valve andthe second loading valve open and close in response to the delivery sidepressure to change a position of the actuator and thereby modulate theposition of the process control valve.

Further, a variable pressure controller is also described and claimed.Generally speaking, the controller is comprised of a first fluidinterface for coupling to a fluid line upstream of a process controlvalve, a sensing mechanism positioned at the first fluid interface andresponsive to a pressure in the fluid line upstream of a process controlvalve, a first loading valve responsive to the sensing mechanism, asecond loading valve responsive to the sensing mechanism, a firstmanifold comprised of two outlet ports, wherein one outlet port iscoupled to a first channel fluidly coupled to the first loading valveand one outlet port is coupled to a second channel fluidly coupled tothe second loading valve, and a second manifold comprised of two outletports, wherein one outlet port is coupled to a first channel fluidlycoupled to the first loading valve and one outlet port coupled to asecond channel fluidly coupled to the second loading valve.

In a specific embodiment of the VPC, at least one module capable ofinterfacing with at least one of the first manifold and the secondmanifold. Additionally, the first loading valve and the second loadingvalve may be one of either a “normally closed” or “normally open” valveconfiguration. The pair of loading valves may be similar or dissimilarto one another.

The described features may be combined as appropriate, as would beapparent to one of skill in the art reading this disclosure. Many ofthese features and combinations will be more readily apparent withreference to the following detailed description and the appended drawingfigures.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of facilitating an understanding of the subject mattersought to be protected, there are illustrated in the accompanyingdrawings embodiments thereof, from an inspection of which, whenconsidered in connection with the following description, the subjectmatter sought to be protected, its construction and operation, and manyof its advantages should be readily understood and appreciated.

FIG. 1 is a schematic of an embodiment of the VPC power module andmanifolds illustrating the plug-and-play versatility of the system;

FIG. 2 is a schematic of an embodiment of a double-acting system withtwo normally-closed loading valves illustrating a condition where thedownstream pressure set-point is satisfied and the system is in a steadystate with the process control valve at a first position;

FIG. 3 is a schematic of the embodiment of FIG. 2 illustrating acondition where the downstream pressure rises above a set-point and theprocess control valve reacts to close further;

FIG. 4 is a schematic of the embodiment of FIG. 2 illustrating acondition where the downstream pressure returns to a set-point and thesystem is again in a steady state with the process control valve at asecond position;

FIG. 5 is a schematic of the embodiment of FIG. 2 illustrating acondition where the downstream pressure falls below a set-point and theprocess control valve reacts to open further;

FIG. 6 is a schematic of the embodiment of FIG. 2 illustrating acondition where the downstream pressure returns to a target pressure(i.e., set-point) and the system is once again in a steady state withthe process control valve at a third position;

FIGS. 7A-E are a sequence of schematics, similar to FIGS. 2-6, of anembodiment of a double-acting system with two normally open loadingvalves illustrating steady state and upset conditions of the system;

FIGS. 8A-E are a sequence of schematics, similar to FIGS. 2-6, of anembodiment of a single-acting system with two normally-closed loadingvalves illustrating steady state and upset conditions of the system;

FIGS. 9A-E are a sequence of schematics, similar to FIGS. 2-6, ofanother embodiment of a single-acting system with the addition of a“derivative” function adjustment and with two normally-closed loadingvalves illustrating steady state and upset conditions of the system;

FIG. 10 is a cross-sectional view of one valve section of an embodimentof the VPC power module showing the interchangeability of anormally-closed loading valve and a normally-open loading valve;

FIG. 11 is a schematic illustrating a single-acting VPC with anormally-closed loading valve configuration and a proportional valveposition feedback acting as a pneumatic valve positioner;

FIG. 12 is a schematic showing a system having a VPC having dissimilarnormally-closed loading valve and a normally-open loading valve withindependent sensitivity adjustments for each loading valve;

FIGS. 13-13 d are various views of an optional valve manual override(VMO), including illustrating the VMO in automatic mode, neutral mode,open mode, and closed mode, and demonstrating manifold configurationbetween VMO body and pneumatic connection ports;

FIGS. 14 and 15 illustrate an embodiment of the VPC power module and theinterchangeable manifolds; and

FIGS. 16A/B through 29A/B are schematics of the numerous systemvariations (FIGS. 16A-29A) and the corresponding VPC model (FIGS.16B-29B).

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

While this invention is susceptible of embodiments in many differentforms, there is shown in the drawings and will herein be described indetail a preferred embodiment of the invention with the understandingthat the present disclosure is to be considered as an exemplification ofthe principles of the invention and is not intended to limit the broadaspect of the invention to embodiments illustrated.

Referring to FIGS. 1-29, there are illustrated embodiments of a fluidline control system, the system being generally referenced in thedrawing figures by the numeral 10. The control system 10 is comprised ofa fluid line 12 having a process control valve 14 coupled therein and avariable pressure controller (VPC) 20 indirectly coupled to the processcontrol valve 14. The process control valve 14 has a supply sidepressure (P1) and a delivery side pressure (P2), the latter of which iscontrolled through operation of the process control valve 14. The VPC 20is comprised of a power module 22 and interchangeable manifolds 30 toachieve different configurations/models, as further explained below.

Process Control Valve

In the embodiment of FIGS. 2-6, the process control valve 14 is directlyoperated by a pneumatic actuator 32 having a first (or upper) pressurechamber 34 and a second (or lower) pressure chamber 36. The pressurechambers, 34 and 36, are fluidly coupled to first and second loadingvalves, 40 and 42, respectively, through adjustable orifices, 44A and44B. In the double-acting models of the system 10, the process controlvalve is operated pneumatically, requiring the fluid pressures in thefirst and second chambers, 34 and 36, to move the actuator in eitherdirection. Comparatively, in the single-acting embodiments, the processcontrol valve 14 includes a spring-piston actuator 32 (e.g., FIG. 18A),where the fluid pressure of the system 10 is used to drive the actuatorin a single direction against the force of the spring 41. Alternatively,the actuator of the process control valve 14 may be operated by aspring/diaphragm 50 (e.g., FIG. 21A). Either of the embodimentsdescribed for actuator 32 of the process control valve 14 for thesingle-acting models may be reversed for particular applications (e.g.,FIGS. 19 and 26).

Loading Valves

The loading valves of the VPC power module 22 are preferably loadingvalves, 40, 42, which are preferably normally closed valves. Thesevalves operate in response to movement of an internal mechanism 16,which is in turn responsive to a control spring 24 and sensing diaphragm26 coupled to a sensing pressure at the delivery side of the processcontrol valve 14. A set-point of the delivery side pressure (P2) is setvia set-point adjustment screw 28. Alternatively, as shown in FIG. 10,the valves may utilize loading valves 45 (FIG. 10), which are of anormally-open configuration. As two loading valves are used, the pair ofloading valves may be similar (i.e., both normally closed loading valvesor both normally open loading valves) or the valves may be dissimilar(i.e., one normally closed loading valve and one normally open loadingvalve).

Operation of Double-Acting VPC System

Generally speaking, operations of the system 10 using different modelsof the VPC 20 are similar. In a double-acting model, when the sensingpressure is equal to the VPC set-point, the net force on the VPC powermodule 22 is zero. This is the equilibrium or “balanced” condition wherethe sensing pressure that pushes down on a sensing diaphragm 26 and theforce of the control spring 24 that pulls up on the sensing diaphragm 26are equal. When the VPC 20 achieves equilibrium (e.g., FIG. 2), the toploading valve 40 and bottom loading valve 42 will remain closedmaintaining a constant output pressure to the top and bottom chambers,34 and 36, respectively, of the process control valve actuator 32. TheVPC will exhibit zero emissions at this state.

From the balanced position two possible scenarios can occur: the sensingpressure can rise above the set point, or the sensing pressure can fallbelow the set-point. If the sensing pressure rises above the VPCset-point (e.g., FIG. 3), the net force on the VPC power module 22 isdownward. The top loading valve 40 will open and divert pressure fromthe top chamber 34 of the double acting actuator 32 to exhaust. Thebottom loading valve 42 will remain closed and full supply pressureshall continue to be applied to the bottom chamber 36 of the doubleacting actuator 32. The combination of these actions creates adifferential pressure to be applied to the double acting actuator 32that will move the process control valve 14 toward the closed position.

FIG. 4 illustrates the resulting corrective action of the closed processcontrol valve.

Conversely, if the sensing pressure falls below the VPC set-point (e.g.,FIG. 5), the net force on the VPC power module 22 is upward. The bottomloading valve 42 will open and divert pressure from the bottom chamber36 of the double acting actuator 32 to exhaust. The top loading valve 40will remain closed and full supply pressure shall continue to be appliedto the top chamber 34 of the double acting actuator 32. The combinationof these actions creates a differential pressure to be applied to thedouble acting actuator 32 that will move the process control valvetoward the open position.

FIG. 6 illustrates the resulting corrective action of the open processcontrol valve.

Remaining with double-acting VPC model of FIGS. 2-6, a step-wiseoperation of an embodiment of the system 10 is provided below.

With reference to FIG. 2, the following is illustrated:

-   -   a. The energy to operate the actuated process control valve 14        is obtained from the differential between supply gas pressure        and exhaust pressure.    -   b. When the downstream pressure (P2) is equal to a set-point a        force equilibrium will exist between the VPC sensing diaphragm        26 and the control spring 24.    -   c. The force equilibrium results in the VPC internal mechanism        16 being centered.    -   d. With the VPC mechanism 16 centered, the first loading valve        40 and the second loading valve 42 remain closed and full supply        pressure passes through the adjustable orifices, 44A and 44B,        and load both pressure chambers 34 and 36 of the pneumatic        actuator 32 equally.    -   e. At the steady state centered position, the VPC 20 achieves        ZERO steady exhaust.

With reference to FIG. 3, the following is illustrated:

-   -   a. When the downstream pressure (P2) is rises above set-point        the VPC sensing diaphragm 26 force will exceed the control        spring 24 force.    -   b. The downward force imbalance results in the VPC internal        mechanism 16 shifting downward.    -   c. With the VPC internal mechanism 16 shifting downward, the        first loading valve 40 will open slightly and second loading        valve 42 will remain closed.    -   d. When the first loading valve 40 opens it causes the pressure        loading the first pressure chamber 34 of the pneumatic actuator        32 to be directed to the exhaust 46.    -   e. The second loading valve 42 remains closed causing full        supply gas pressure to pass through the adjustable orifice 44        loading the second pressure chamber 36 of the valve actuator 32.    -   f. With the pressure differential across the valve actuator 32,        the process control valve 14 moves toward the CLOSED position.

With reference to FIG. 4, the following is illustrated:

-   -   a. When the process control valve 14 moves toward the CLOSED        position, the downstream pressure will drop and return to a        value equal to the set-point.    -   b. When the downstream pressure (P2) is equal to set-point, a        force equilibrium will exist between the VPC sensing diaphragm        26 and the control spring 24.    -   c. The force equilibrium results in the VPC internal mechanism        16 being centered.    -   d. With the VPC internal mechanism 16 centered, the first        loading valve 40 and the second loading valve 42 remain closed        and full supply pressure passes through the adjustable orifices        44A and 44B and loads both pressure chambers, 34 and 36, of the        pneumatic actuator 32 equally.    -   e. At the steady state centered position, the VPC 20 achieves        ZERO steady exhaust.

With reference to FIG. 5, the following is illustrated:

-   -   a. When the downstream pressure (P2) is falls below the        set-point the VPC control spring 24 force will exceed the        sensing diaphragm 26 force.    -   b. The upward force imbalance results in the VPC internal        mechanism 16 shifting upward (as indicated by the arrow).    -   c. With the VPC internal mechanism 16 shifting upward, the        second loading valve 42 will open slightly and first loading        valve 40 will remain closed.    -   d. When the second loading valve 42 opens, it causes the        pressure loading the second pressure chamber 36 of the pneumatic        actuator 32 to be directed to the exhaust 46.    -   e. The first loading valve 40 remains closed, causing full        supply gas pressure to pass through the adjustable orifice 44        loading the first pressure chamber 34 of the valve actuator 32.    -   f. With the pressure differential across the valve actuator 32,        the process control valve 14 moves toward the OPEN position.    -   g. When the process control valve 14 moves toward OPEN position,        the downstream pressure will rise and return to a value equal to        the set-point.

With reference to FIG. 6, the following is illustrated:

-   -   a. When the downstream pressure (P2) is equal to a set-point, a        force equilibrium will exist between the VPC sensing diaphragm        26 and the control spring 24.    -   b. The force equilibrium results in the VPC internal mechanism        16 being centered.    -   c. With the VPC internal mechanism 16 centered, the first and        second loading valves, 40 and 42, remain closed and full supply        pressure passes through the adjustable orifices, 44A and 44B,        and loads both pressure chambers, 34 and 36, of the pneumatic        actuator 32 equally.    -   d. At the steady state centered position, the VPC 20 achieves        ZERO steady exhaust.

While FIGS. 2-6 illustrate and the above describes a double-actingactuator operated process control valve using normally-closed loadingvalves, it should be understood that systems using the normally-openloading valves operate similarly. For example, the steady state andupset state conditions are illustrated in FIGS. 7A-E featuring a VPCwith normally-open valves.

Operation of Single-Acting VPC System

Similarly, referring to FIGS. 8A-E and 9A-E, a single-acting version canbe used and works similarly. A notable difference is that the firstloading valve 40 and the second loading valve 42 would be connected incommon and would work synchronously. These valves, 40 and 42, wouldstill be normally closed and would translate to “cylinder load” and“cylinder unload.”

That is, for single-acting systems where a single pressure output isinvolved, there shall be one valve designated as the “load” valve andone valve designated as the “unload” valve. Each valve shall be normallyclosed for this type of system. The “load” and “unload” valves areconnected to a common pressurized system. In this configuration, the VPC20 has three different states: (1) steady state; (2) unloading state;and (3) loading state.

In the steady state, both the “load” and “unload” valves are closed,resulting in no pressurizing or depressurizing of the pneumatic actuatorsystem. The process control valve 14 is said to be in a steady state orstatic.

When an upset in the process variable occurs, the VPC 20 may enter theunload state or loading state. In the unload state, the force unbalancebetween the VPC sensing diaphragm 26 and the control spring 24 causes ashift of the VPC 20 to open the “unload” valve and maintain the “load”valve in a closed position. This causes the system 10 to vent or exhaustpressure from the pneumatic actuator 32 resulting in a new position ofthe process control valve 14. Conversely, when an upset occurs to placethe VPC 20 in the “loading” state, the unbalance between the sensingdiaphragm 26 and the control spring 24 causes a shift of the VPC 20 toopen the “load” valve and keep the “unload” valve closed. This causesthe system 10 to increase pressure to the pneumatic actuator 32resulting in a new position of the process control valve. Ultimately, inboth cases, the new position of the process control valve 14 will resultin attainment of equilibrium and return to the steady state, asdescribed above.

Additionally, in the single-acting (SA) model of the VPC, when thesensing pressure is equal to the VPC set-point, the net force on the VPCpower module 22 is zero. As noted, this is an equilibrium conditionwhere the sensing pressure that pushes down on the sensing diaphragm 26and the force of the control spring 24 that pulls up on the sensingdiaphragm 26 are equal. When the VPC 20 achieves this equilibrium, thesupply loading valve 40 and exhaust loading valve 42 will remain closedmaintaining a constant output pressure to the process control valve 14.The VPC 20 will exhibit zero emissions at this state.

During operation, the equilibrium or steady state (static) is preferred,so the system operates to return to this state whenever an upset occurs.As noted, two possible scenarios can occur from the balance state: thesensing pressure can rise above the set point or fall below the setpoint. If the sensing pressure rises above the VPC set-point, the netforce on the VPC power module is downward. The exhaust loading valvewill close or stay closed. The supply loading valve opens, increasingthe flow of supply gas to the output port. The combination of theseactions creates a rise in output pressure. If the sensing pressure fallsbelow the VPC set-point the net force on the VPC power module is upward.Now the supply loading valve will close or stay closed and the exhaustloading valve opens, increasing the flow of gas to the exhaust port. Thecombination of these actions decreases the output pressure. In order tocontrol how much gas passes through the loading valve, adjustableorifices are installed to restrict the flow via the supply and theexhaust.

Modularity of VPC

A key aspect of the system 10 is the modularity of the VPC 20. A modularformat of the VPC 20 is illustrated in FIG. 1. The modular format ofpower modules 30 and the internal loading valve logic (FIG. 10) providethe ability to configure the device for double-acting (DA) output orsingle-acting (SA) output within the same system. Existing technologydoes not offer a modular format that allows reconfiguration between thedouble-acting output and single-acting output configurations.

Accordingly, the VPC 20 is capable of being configured in a number ofdifferent models as a result of the adaptability of the single platformpower module 22 and the various “plug-and-play” modules. Exemplaryembodiments of these “plug-and-play” modules (labeled 1-4) to formdiscrete VPC models (labeled 1-5, with corresponding labeled modulesforming the particular VPC model) are set forth in FIG. 1. Each model1-5 corresponds to a set of operating parameters referenced in TABLE 1below. More detailed illustrations and descriptions of such modules andVPC models, as well as possible alternatives and accessory devices,follow.

TABLE 1 Controller Model VPC-SA- VPC-SA- VPC-SA- VPC-DA- VPC-DA- BVBV-ID BV-GAP BV SN Type Variable Variable Discrete Variable Variable(On-Off) Outputs Single Acting (1) Double Acting (2) InternalNormally-Closed Loading Valve Normally Valve Open Logic Loading ValveSetpointl 1.25-1500 psig (9.0-10,342 kPa) Range Temperature −20° F. to+160° F. (−29° C. to +71° C.) Range

The various VPC models are so configured to be applicable to differentfluid systems. In operation, the embodiments operate in a similarmanner, with variations such as flow direction, valving, etc., dictatedby the accompanying modules and accessory devices. And the simplemodularity allows conversion between models. For example, the VPC hasthe ability to convert between a normally open loading valve style (SN)to normally closed loading valves (BV). Further, the manifoldingprovided by the power module 22 provides the ability to convert to andfrom single acting to double acting models. Additionally, whenconfigured as a single acting model, the VPC can convert between “directacting” and “reverse acting” control logic.

Referring to FIGS. 16-29 (A and B), the modularity of the VPC 20 can bemost readily appreciated. In these figures the numerous VPC models areshown schematically placed within a fluid control system 10 (i.e., FIGS.16A-29A) and labeled for adjusting the set-point screw 28 andsensitivity (i.e., FIGS. 16B-29B).

VPC Modules

Referring to FIGS. 1, 14 and 15, several different manifolds 30 areillustrated. These manifolds 30 connectable to the VPC power module 22and create the various VPC models described. As illustrated, theindividual manifolds 30 may include various configurations, channels andadjustable orifices to accommodate single-acting and double-actingconfigurations, as well as normally-closed loading valve andnormally-open loading valve configurations. The manifolds 30 connect andbolt (or otherwise lock) onto the power module 22.

System Accessories

Referring now to FIGS. 11-13, numerous system 10 accessories can beviewed. These accessories also add to the modularity of the VPC 20. Asnoted above, the VPC 20 may be configured with either normally openloading valves (seat & nozzle valves 45) or normally closed (loadingvalves 40) internal logic using the same VPC base platform 22.Interchangeable internal valve format “Logic Exchange” (see FIG. 10)allows the system 10 to be configured for multiple control applications.

As shown in FIG. 1, the “connecting” manifolds 23 of the VPC powermodule 22 provide unique flow conditioning that optimizes flowcharacteristics of internal logic (loading valves 40 and 42), allowinggreater control capabilities of the VPC 20. This is particularlyimportant when coupled with additional control devices such as a volumebooster 33 (see FIG. 12) and a pneumatic positioner 35 (see FIG. 11).Existing technology does not integrate any “flow conditioning” viamanifolding, which lessens control capabilities.

The VPC derivative adjustment (orifice) is pneumatically coupled withthe VPC output pressure via installation in same manifold which providesimproved control capabilities. The derivative adjustment is anadjustable orifice (restriction) that is installed in parallel with theoutput to the control element (actuator 32 or pneumatic positioner 35)with a volume tank 37 installed downstream of the derivative adjustment.The resulting configuration provides for a delayed response of the VPCoutput signal to the control element (actuator 32 or valve positioner35). The derivative adjustment affects the rate of response of theoutput to the control element (actuator 32 or valve positioner 35).Existing systems utilize a derivative adjustment (orifice) that isinstalled as a separate component (adjustable orifice) from the outputfunction which does not provide the same optimized characteristics asachieved in the VPC 20 of the present system 10.

The base VPC 20 of system 10 offers numerous additional advantages overexisting technology. As shown in FIG. 12, the VPC 20 allowsincorporation of two (2) dissimilar internal valves (i.e.,normally-closed loading valve and normally-open loading valve) toachieve a completely new control configuration for applicationoptimization. Current technology must utilize two (2) identical internalloading valves due to limitations of design. Also shown, the VPC 20 alsoallows incorporation of two (2) independent sensitivity adjustments foreach internal loading valve to achieve a completely new controlconfiguration for application optimization. Current technology islimited to only a single sensitivity adjustment that affects bothinternal loading valves.

The VPC 20 may also be configured as a proportional device with amechanical feedback to achieve a “diaphragm type” valve positioner 39,as shown in FIG. 11. Current technology incorporates a mechanicalfeedback that directly couples the diaphragm module with the powermodule in a linear arrangement. A diaphragm type valve positioner 39incorporates a mechanical feedback that separates the diaphragm moduleand the power module. The design incorporates pivoted beam component tocouple the power module 22 and the diaphragm module 39, also shown inFIG. 11.

The base VPC 20 provides Integral function (I) and Derivative function(D) adjustments. More demanding control applications may requireaddition of a Proportional function (P) adjustment in a “PID” typecontroller. The present system 10 utilizes a continuous typeProportional function (P) adjustment that incorporates a pivoted beamwith an adjustable fulcrum. Existing technology does not have acontinuous Proportional function (P) adjustment, but utilizes aselection of interchangeable components to achieve only discreteProportional function (P) values.

Optionally, with reference to FIG. 13-13 d, the system 10 may include avalve manual override (VMO) 46, which is a six-way, five-position valveutilized in conjunction with the VPC 20. The VMO 46 provides an abilityto override any of the system configurations and manually operate theprocess control valve 14 to which the VPC 20 is coupled. In contrast,current technology is installed via threaded plumbing connections andmultiple pneumatic tubing lines. The current system 10 allows the VMO 46to be installed as an integral component with the VPC 20 utilizing theunique manifold 23, thereby minimizing the need for any externalplumbing connections and simplifying the design. Additionally, themanifolds 23 of the system 10 allow for installation and removal of theVMO 46 without removal of any threaded plumbing fittings. Rotary typeVMO and linear ported type VMO may be used. In the case of the rotarytype VMO, the device is used to interrupt and allow manual control ofthe pneumatic output of the pilot by manually rotating ports. The linearported type VMO also interrupts and allows manual control of thepneumatic output of the pilot, but does so by shifting of a linearported valve system.

Other key alternate components and embodiments of the system 10 and VPC20 are set forth in the paragraphs below.

As previously mentioned, the VPC 20 can use two different internalvalves fluidly coupled to the actuator 32. Known existing designs havealways used the same internal valves in order to achieve a controlfunction. Comparatively, the loading valves of the present system 10 canbe either normally-open type loading valves or normally-closed typeloading valves. For example, the VPC 20 can be constructed using onenormally-open type loading valve and one normally-closed type loadingvalve. Additional adjustments would be needed in order to tune eachloading valve individually, but those skilled in the art wouldunderstand how to make such adjustments. Such a configuration can beused, for example, where a volume booster 33 (FIG. 12) is needed in onedirection but not is the opposite direction.

As those skilled in the art will appreciate, existing pneumaticcontrollers are available in two configurations: Bourdon tube plus relayand direct diaphragm. The Bourdon tube plus relay is available with allvariable P I+D functions. The direct diaphragm controller is onlyavailable with variable I+D and selectable P functions. However, the VPC20 can also be built on the diaphragm principal with all P+I+D functionsavailable as variable.

With respect to the use of a pneumatic positioner 35, existing devicesare available as one of either a relay type, spool valve type ordiaphragm type positioner. The relay positioner and spool valvepositioner are both available with rotary or linear feedback. However,the diaphragm positioner is currently only available with a linearfeedback. The present system 10 provides a diaphragm positioner withrotary feedback or linear feedback. The rotary feedback will have afeedback beam driven by the sensing diaphragm and counterbalanced by thepower diaphragms and range extension spring.

Other possible design alterations include the following:

-   -   A. Combining I and D orifice in one manifold;    -   B. Using a smaller volume tank;    -   C. Using ID controller as the first stage cut controller over PI        and over PID;    -   D. Use of 0.001″ hard coat anodizing to create a barrier between        aluminum and SS screws, which eliminates electrolysis effect and        aluminum corrosion;    -   E. 5.225 and 1500 sensing chambers built as independent chambers        versus existing technology design; and    -   F. Six common springs for all design versus several cartridges        for existing technology.

The matter set forth in the foregoing description and accompanyingdrawings is offered by way of illustration only and not as a limitation.While particular embodiments have been shown and described, it will beapparent to those skilled in the art that changes and modifications maybe made without departing from the broader aspects of applicants'contribution. The actual scope of the protection sought is intended tobe defined in the following claims when viewed in their properperspective based on the prior art.

What is claimed is:
 1. A method for controlling a fluid supply through adelivery line having a process control valve therein to maintain asupply side pressure and a delivery side pressure, and a pneumaticactuator having a first pressure chamber and a second pressure chamberand used to operate the process control valve, the method comprising thesteps of: setting a delivery side target pressure range for the fluidsupply; sensing the delivery side pressure; operating the pneumaticactuator in one of the following ways: maintaining the actuator in astatic state when the delivery side pressure is within the target range;moving the actuator to open the process control valve when the deliveryside pressure is below the target range; and moving the actuator toclose the process control valve when the delivery side pressure is abovethe target range; wherein, the first and second pressure chambers of theactuator are responsive to a first loading valve fluidly coupled to thefirst pressure chamber and a second loading valve fluidly coupled to thesecond pressure chamber, and the first loading valve and the secondloading valve open and close in response to the delivery side pressureto change a position of the actuator and thereby operate the processcontrol valve.
 2. The method for controlling a fluid supply through adelivery line as set forth in claim 1, further comprising the step ofcombining I and D orifices in a single manifold.
 3. The method forcontrolling a fluid supply through a delivery line as set forth in claim1, further comprising the step of using 0.001″ hardcoat anodizing tocreate a barrier between aluminum and stainless steel screws toeliminate electrolysis and aluminum corrosion.